Method of producing sulfur dioxid of commercially uniform temperature and concentration.



.uErTEn sTaTEs EETEET oEETcE.

JOHN L. TUFTS, vOF BOSTON, lvlAbSAffHlIGTTS.

METHOD OF PRODUCING SULFUR DIOXID OF CMMERCIALLY UNIFORM TEMPERA'LIRE AND CONCENTRATION. u

PatenteaJune te, 190s.

Application led July 29, 1907. Serial No. 386,159.

` T o allwliom it may conce-rn: i

Be it known that I, JOHN L. TUrTs, a citizen of the United States, residing at Boston, in the county of Suffolk and State of Massachusetts, have 'invented certain new and method whereby dilute sulfur dioxid such as results from pyriticy smelting operations or the like may be rendered available for use in -various chemical processes, for instance, in the manufacture of paper pulp by the snllitc process, the production of sulfuric acid, etc. T his'object is accomplished in the preferred embodiment of the invention by passing the dilute gas rich in oxygen upwardly through a bed of hot ore in suitable pyrites burners, whereby 'oxygen is consumed and the percentage of sulfur dioXid largely increased. lf as is usually the case the dilute-gas is subject to wide fiuctuations either in respect to concentration of sulfur dioxid or temperature, it is preferred to subject the same to an equalizing operation before enriching it. The initial high temperature of the gas is conserved as far as practicable throughout the treatment.

ln order that the invention may be clearly understood the method will be described by way of example as applied to certain specific conditions whereinl the gases are subject to wide Vfluctuations both of concentration and temperature, itvbeing understood that the mode of application of the method will vary with the specilic conditions of production of the gas, and with the requirements of the process for its utilization.

Under the specific conditions referred to thc dilute sulfur dioxid is derived from set of pyritic smelfcrs and is subject to a periodical variation of concentration from 2% to 141-52 by volume of sulfur dioxid,l the usual average concentration being approximately 4%. The concentration varies in accordance with the stage of the operation as follows: After the introduction ofthe fresh charge but before its ignition the concentraercentafe of sulfur dicxid varies not oni. l

with the stage of the operation but also in" accordance with the quantity and composi-;y tion of the charge, and according to wlw-ether the smelters are running hot or cold./Y The percentage of oxygen varies inversely as the sulfur dioxid, from 19% to 7% by volume. The temperature of the gas varies from 400 to 1,5000 Ff, according to the period of the charge, averaging about 1,00()o F. The average interval between maximum and minimum temperature of the gases, and between maximum and minimum concentration of sulfur dioxid, is nine minutes, but varies from four to thirty minutes, In order to render a gaseous product of this character available for commercial uses, it is necessary that it should be subjected to an equalizing operation. ln order to render it available for the specific use of the productionof sulfuric acid by means of an iron oxid contact l mass, in which case the best practice requires a uniform gas containing 67,3 by volume sulfur dioxid at a uniform temperature of 1,15()o F., l may ,proceed as follows: The from the smelters is conducted lirst through a heavy-walled dust-chamber of masonry surrounded by a shell of sheet-iron, a space being left between the masonry and the iron and filled with a heat insulating material such as kicselguhr. From the dust-chamber the gas is led to an equalizer, which may comprise a thick brick-walled chamber having a heat insulating coating and covered with sheet-iron; preferably thel equalizer is provided interiorly with a filling or checkerwork of refractory brick, tile or the like. The capacity of the equalizer should be sulficient to hold the gas delivered during an appreciable period, in order to -reduce the variation in its composition; and it should furthermore be of such heat capacity and design. that the temperature variation can be. elininated to the extent desired. The `llue connecting the lust-chamber with the equalizer is provided with a suitably controlled inlet for air, and sufficient air is introduced at the periods of the operation. in which the gas delivered of high concentration to suitably reduce the exc ess of sulfur dioxid, Preferably the gases are conducted through the apparatus under slight suction, in which case the air may readily beiuhnitted as desired,A

The gaseous product flowing from the equalizer is as compared with the gas l rom the smelters moderately uniform in temperal lm'is,'ati`ording distributing space for the gas.

ln these burners the combustion becomes more intense when the sulfur dioxid is low and the oxygen high and less intense when these conditions are reversed, the result being that the inal as from the burners is of approximately uni crm high temperature and concentration, and is suited for direct introduction into an iron oxid contact mass; it is also suitable for direct introduction into a Glover tower and sulfuric acid chambers, or

into the suli'ite digesters; or after suitable coolnum contact mass. y

For a 'full understanding of the'invention reference is made to the accompanying drawing wherein the ligure is a plan view of one form of installation for practicingthe'method, the upper portion of the equalizer being broken away.

In said drawing l represents a Group of smeltinff furnaces for pyritic ores, the gases from which are dischar edthrough lues 2 into a common flue' lea ing to a dust chamber 4. l

5 represents .the equalizer, having double walls 6, 7 for heat-insulation, and interiorly filled with checker-Work 8 on either side of a partition 9. l. 1

10 represents an air-inlet located in the gas iiue between the dust chamber and the equalizer.

From the equalizer the gases flow directly to the burners represented at 11, and the iinal gases are conveyed from the burners through the Hue 1,2 for further utilization.A

The expression combustion of sulfur occurring in the claims is intended to cover the combustion of free sulfur, and also the combustion of combined sulfur in sulid ores; in the latter case itwill be 'understood that the oxygen combines not only With "the sulfur but with thel'metalof the ore, whereby .the

gases are heated to a somewhat higher temperature.

I claim: y

1. The method of producing sulfur dioXid ofy connnercially,uniform` temperature and concentration, which consists in iirst preparing dilute and variable gases containing sulfur dioxid, separating solids therefrom, then equalizing the temperature and concentration of said gases by diluting the same With variable proportions of air, and thereafter lutilizlng the gases for the combustlon of sul- 'fur and thereby equali'zing the temperature and increasing the concentration of the same. I

2. In a method of roducing sulfur dioXid of connnerciallyuniform temperature and concentration, the stepswhich consist in iirst preparing dilute and variable gases containing sulfur dioxid, and thereafter utilizing said gases for the combustion of sulfur, and thereby cqualizing the temperature and increasing the concentration of the same.

3. In a method of producing sulfur 'dioxid of commercially uniiorm/ temperature and concentration, the steps which consist in' first preparing dilute and variable gases containing suliur dioxid, 'then subjecting said 'gases to an equalizing operation, and thereafter utllizmg said gases for the combustion I of sulfur, and thereby equalizing the temperae ture and increasing 'the concentration of the same.

4. The method of producing sulfur dioXid of commercially uni orm temperature and concentration, which consists in iirst preparing dilute and vz. viable gases containmg sulfur dioxid, then U'ualizmg the temperature and concentration of said gases by diluting the same with variable proportions of air, and thereafter utilizing the gases for the combustion of sulfur and thereby equalizing the temperature and increasing the conceni, 95

tration of the same.`

In testimony whereof, I affix. my'signature in presence of two-witnesses.

. JOHN. L. rur'rs.

Witnesses: A

,v EvEnE'rT E. BRAINARD, ALBERT C.G1LBER1I. 

